The present invention relates generally to a hinge assembly such as that used with vehicle doors, and more particularly to a hydraulic infinite door check cylinder assembly that includes a controlled check release which maintains a door at a desired position unless a predetermined check effort is applied to release a needle from a closed or checked position, allowing movement of hydraulic fluid through a piston disposed in a cylinder bore.
Mechanical checks are typically used in vehicle hinge assemblies to check door movement. Such mechanical checks have a limited number of door check positions. Further, mechanical checks typically loose a large portion of their ability to check movement of a vehicle door within three to five years. Mechanical checks are also subject to particulate contamination, further deteriorating their ability to function.
Pressurized gas cylinders are also used with vehicle hinge assemblies. Door movement using pressurized gas cylinders may typically only be counterbalanced within a very narrow temperature range. Inert gases are subject to large density variations resulting from changes in temperature. As a result, pressurized gas cylinders do not readily counterbalance a door in an open position under low temperatures, and yet over assist the same door from such an open position under elevated temperatures. Pressurized gas cylinders are also subject to constant stress because of the pressurized nature of the gases within the cylinders. Such stress may result in cylinder leakage and failure.
Despite their limitations, mechanical checks and pressurized gas cylinders have continued to be favored because of user objection to other means of door checking that result in an audible "pop" when a check release is activated to permit door movement.